From eaf649ee9bdfa7e20ba381a505e2c5b48501c242 Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Thu, 9 Feb 2023 20:41:02 +0000
Subject: [PATCH] networkd: Enumerate all links on startup

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/networkd/daemon.c | 16 +++++++++-------
 src/networkd/daemon.h |  7 +++++++
 src/networkd/link.c   |  7 +++++++
 src/networkd/link.h   |  2 ++
 src/networkd/links.c  | 39 +++++++++++++++++++++++++++++++++++++--
 5 files changed, 62 insertions(+), 9 deletions(-)

diff --git a/src/networkd/daemon.c b/src/networkd/daemon.c
index 27b118e9..88ce8e71 100644
--- a/src/networkd/daemon.c
+++ b/src/networkd/daemon.c
@@ -31,6 +31,7 @@
 #include "config.h"
 #include "daemon.h"
 #include "devmon.h"
+#include "link.h"
 #include "links.h"
 #include "logging.h"
 #include "zone.h"
@@ -193,12 +194,6 @@ static int nw_start_device_monitor(struct nw_daemon* daemon) {
 	return 0;
 }
 
-static int _rtnl_dummy(sd_netlink* rtnl, sd_netlink_message* message, void* data) {
-	DEBUG("_rtnl_dummy called\n");
-
-	return 0;
-}
-
 static int nw_daemon_connect_rtnl(struct nw_daemon* daemon, int fd) {
 	int r;
 
@@ -224,7 +219,7 @@ static int nw_daemon_connect_rtnl(struct nw_daemon* daemon, int fd) {
 	}
 
 	// Register callback for new interfaces
-	r = sd_netlink_add_match(daemon->rtnl, NULL, RTM_NEWLINK, _rtnl_dummy, NULL,
+	r = sd_netlink_add_match(daemon->rtnl, NULL, RTM_NEWLINK, nw_link_process, NULL,
 			daemon, "networkd-RTM_NEWLINK");
 	if (r < 0) {
 		ERROR("Could not register RTM_NEWLINK: %m\n");
@@ -394,6 +389,13 @@ int nw_daemon_reload(struct nw_daemon* daemon) {
 	return 0;
 }
 
+/*
+	Netlink
+*/
+sd_netlink* nw_daemon_get_rtnl(struct nw_daemon* daemon) {
+	return daemon->rtnl;
+}
+
 /*
 	Zones
 */
diff --git a/src/networkd/daemon.h b/src/networkd/daemon.h
index 891c297a..543685f5 100644
--- a/src/networkd/daemon.h
+++ b/src/networkd/daemon.h
@@ -21,6 +21,8 @@
 #ifndef NETWORKD_DAEMON_H
 #define NETWORKD_DAEMON_H
 
+#include <systemd/sd-netlink.h>
+
 #include "zone.h"
 
 struct nw_daemon;
@@ -34,6 +36,11 @@ int nw_daemon_run(struct nw_daemon* daemon);
 
 int nw_daemon_reload(struct nw_daemon* daemon);
 
+/*
+	Netlink
+*/
+sd_netlink* nw_daemon_get_rtnl(struct nw_daemon* daemon);
+
 /*
 	Zones
 */
diff --git a/src/networkd/link.c b/src/networkd/link.c
index 06e31017..ec0593b0 100644
--- a/src/networkd/link.c
+++ b/src/networkd/link.c
@@ -23,6 +23,7 @@
 
 #include "daemon.h"
 #include "link.h"
+#include "logging.h"
 
 struct nw_link {
 	struct nw_daemon* daemon;
@@ -70,3 +71,9 @@ struct nw_link* nw_link_unref(struct nw_link* link) {
 	nw_link_free(link);
 	return NULL;
 }
+
+int nw_link_process(sd_netlink* rtnl, sd_netlink_message* message, void* data) {
+	DEBUG("nw_link_process called\n");
+
+	return 0;
+}
diff --git a/src/networkd/link.h b/src/networkd/link.h
index 6ffe843c..6003133d 100644
--- a/src/networkd/link.h
+++ b/src/networkd/link.h
@@ -30,4 +30,6 @@ int nw_link_create(struct nw_link** link, struct nw_daemon* daemon, int ifindex)
 struct nw_link* nw_link_ref(struct nw_link* link);
 struct nw_link* nw_link_unref(struct nw_link* link);
 
+int nw_link_process(sd_netlink* rtnl, sd_netlink_message* message, void* data);
+
 #endif /* NETWORKD_LINK_H */
diff --git a/src/networkd/links.c b/src/networkd/links.c
index b81d6a59..22584f2f 100644
--- a/src/networkd/links.c
+++ b/src/networkd/links.c
@@ -99,7 +99,42 @@ struct nw_links* nw_links_unref(struct nw_links* links) {
 }
 
 int nw_links_enumerate(struct nw_links* links) {
-	// TODO
+	sd_netlink_message* req = NULL;
+	sd_netlink_message* res = NULL;
+	int r;
 
-	return 0;
+	sd_netlink* rtnl = nw_daemon_get_rtnl(links->daemon);
+	if (!rtnl)
+		return 1;
+
+	r = sd_rtnl_message_new_link(rtnl, &req, RTM_GETLINK, 0);
+	if (r < 0)
+		return 1;
+
+	r = sd_netlink_message_set_request_dump(req, 1);
+	if (r < 0)
+		return 1;
+
+	r = sd_netlink_call(rtnl, req, 0, &res);
+	if (r < 0)
+		return 1;
+
+	sd_netlink_message* m = res;
+
+	// Iterate through all replies
+	do {
+		r = nw_link_process(rtnl, m, links->daemon);
+		if (r)
+			goto ERROR;
+	} while ((m = sd_netlink_message_next(m)));
+
+ERROR:
+	if (m)
+		sd_netlink_message_unref(m);
+	if (req)
+		sd_netlink_message_unref(req);
+	if (res)
+		sd_netlink_message_unref(res);
+
+	return r;
 }
-- 
2.47.3